Just returned from the range with NEW BlackMZ performance data to report.
Duration of Firing: 2hr 10 min
Weather:
Temp at time of firing: 29 to 31 degrees fahrenheit.
Barometric Pressure: 30.01 in
Humidity: 49%
Cartridge: .45-70
Primer: CCI 250 Large Magnum Rifle Primer
Propellant: Black MZ- Charge Weight 55.0gr with Over Powder lubricated wad "Bridgers Best"
Projectile: 500grain RNFB Hard Cast Penn Bullet URL-http://
www.pennbullets.com/4570/4570-caliber.html
Brinell Hardeness: 20
Lubricant: Coated in Dupont Dry Teflon- Lube Grooves filled with Kiwi Beeswax/Lanolin
Compression: Heavy
Seating: .015" of top band exposed (slightly high but not fully engaging rifling)
Crimp: Factory Crimp- Lee "Tight"
Weapon: Perdersoli Q Sharps 34" Octagonal Heavy Barrel.
Firing consisted of 2 five round groups. No swabbing between shots, bore evacuated between shots with exhaled breath.
Velocity measured fps with Caldwell BPC placed 5 meters forward of muzzle.
I warmed the barrel up by firing 10 rounds of older BlackMz loads 55 grains under a 350gr bullet with CCI 250 LMRP.
The barrel was cold soaked and close to ambient temperature. Results as follows:
1- 1573
2- 1607
3- 1569
4- 1581
5- 1513
6- 1533
7- 1584
8- 1610
9- 1691
10- 1620
The barrel was warm to touch. I swabbed with wet patches soaked in Hoppes. Dry swabbed till clean.
For record shots were 55gr under a 500gr RNFB with Bridgers Wads and heavy compression by no crimp as Don McDowell suggested.
Results:
1- 1227
2- 1219
3- 1173
4- 1266
5- 1213
6- 1235
7- 1203
8- 1263
9- 1189
10- 1222
AVG= 1220.70
AVG DEV= 21.3
STD DEV= 28.8
I am satisfied that this particular load using BlackMZ demonstrates consistent performance. The next question is how accurate is the load as measured by the groups fired.
I am headed back tomorrow to assess 50 and 100 yard accuracy at this load level. More as I learn it...But I really like BlackMZ.